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Welcome to the site that tries to make sense of chance, risk, luck, uncertainty and probability. Mathematics won't tell us what to do, but we think that understanding the numbers can help us deal with our own uncertainty and allow us to look critically at stories in the media.

Sex by Numbers, by David Spiegelhalter, is now available for purchase!

When my family plans a trip to the beach in Scotland, there is always a high chance of rain. So I always pack everything: from sunscreen to waterproofs. But would I have reached the same conclusion listening to the weather forecast on the radio or when checking the weather app on my phone? And would my husband have done the same?

I’ve had a lot of publicity over the last few days, but none of it was welcome. It arose from the story below from the Daily Telegraph of June 6 with the headline “Britons are having less sex, and Game of Thrones could be to blame, says Cambridge professor”

On Thursday November 19th the printed version of the Guardian had the headline “Experts dispute Hunt's claim on weekend hospital treatment“ [online version here]. But it was not only Health Secretary Jeremy Hunt who gave a misleading statement – the Guardian also made a serious error about statistics.

Surgeons are increasingly subject to statistical monitoring, and named results may be made publicly available. But consider a surgeon in a low-risk specialty who has had a successful and blameless career, until a combination of circumstances, possibly beyond their control, contribute to a single patient dying. They then find they are officially labeled as an ‘outlier’ and subject to formal investigation, all because of a purely statistical criterion. Is this fair?